The 'Most Favoured Nation' (MFN) principle under the WTO mandates that a country must give preferential trade treatment to its closest political allies over other WTO members.

The MFN principle actually requires non-discrimination; if a WTO member grants a special trade favor (like a lower tariff) to one country, it must immediately extend the exact same favor to all other WTO members. Exceptions exist only for Free Trade Agreements or special concessions for developing nations.